Periodontal diseases affect a large proportion of the world's population. New insights into periodontal disease pathogenesis should incorporate the molecular biology dynamics that the periodontium undergoes in response to bacteria and chronic periodontal inflammation. Understanding this sequence of events allows us to delineate important clinical implications that would enable us to determine disease activity while increasing our understanding of the molecular networks behind the patient's susceptibility to periodontal breakdown. Periostin is a matricellular protein relevant for tissue integrity and maturation and is believed to have a function in the periodontium. We hypothesize that Periostin levels are important for proper periodontal homeostasis and periodontal disease pathogenesis and propose conducting studies on the role of Periostin in periodontal function and disease with the following specific aims: Specific Aim 1- To determine the biomechanical mechanism of Periostin regulation. Specific Aim 2- To evaluate the effect of periodontal bacteria and proinflammatory cytokines on Periostin levels. Specific Aim 3- To analyze the protective role of Periostin on periodontal stability in-vivo. Molecules such as Periostin serve as potential novel biomarkers with significant implications to aid in our understanding of periodontal biology relevant to cell-matrix dynamics and homeostasis. Collectively, the available evidence and evolving understanding of the molecular dynamics that determine a patient's susceptibility to periodontal breakdown triggered by periodontal pathogens would assist clinicians on the complex task of identifying important etiologic contributors that could be targeted in the treatment of inflammatory periodontal diseases.